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adding a complication to a time only clock?

Aloha

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What are some considerations a novice should be aware of if they wanted to add a complication (for example day of week) to a clock with a balance wheel escapement (can't have a pendulum do to size restraints and don't want a quartz)?
Could I attach a gear to the minute or hour hand arbor shaft to drive the complication? Some considerations I have thought of...

1) will adding a complication add too much friction? If so....what are possible solutions

a) increase mainspring strength?,
b) pick a longer day movement like 30 day rather than 8 day movement?
c) add second mainspring in parallel?
d) add second mainspring in series?
e) carefully select clock movement to use? any suggestions?


2)what is the best place to attach the complication to the movement?

a) attach gear to the hour hand to power the gears for the complication which would be built over the movemen?
b) attach gear to the minute hand to power the gears for the complication which would be built over the movement?
c) drive it directly off of the mainspring
 
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leeinv66

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I'm moving your post to clock repair as I think it will fit better there.
 

Willie X

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My advice would be to study some of the post WW-II Japanese clocks from around 1960. Many had day/date calendars. Some had the numerals on drums some on disk. They were driven in different ways but all had a string of gears to get the motion down to below the dial.

Myself, I would probably go above the dial with a disk drive, like a moon dial that advances once per day.

It's not rare to see a modern German GF with day, date, and month dials.

Yes, it will drain power from your clock but if the mechanism is very well made there should be no problem.

What kind of movement?

Willie X
 
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Aloha

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My advice would be to study some of the post WW-II Japanese clocks from around 1960. Many had day/date calendars. Some had the numerals on drums some on disk. They were driven in different ways but all had a string of gears to get the motion down to below the dial.

Myself, I would probably go above the dial with a disk drive, like a moon dial that advances once per day.

It's not rare to see a modern German GF with day, date, and month dials.

Yes, it will drain power from your clock but if the mechanism is very well made there should be no problem.

What kind of movement?

Willie X
I'm looking for an 8 day movement (or longer). Other than that I'm open to suggestions on what I should look for. I don't have a specific kind of movement in mind yet but will decide on one once I'm confident that movement will work. I don't mind using an old movement.
 

R. Croswell

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I'm looking for an 8 day movement (or longer). Other than that I'm open to suggestions on what I should look for. I don't have a specific kind of movement in mind yet but will decide on one once I'm confident that movement will work. I don't mind using an old movement.
If you don't already have a movement, my advice would be to search for a movement that already has the features you are looking for. What you describe sounds simple enough to say, but building the "complication" and actually have it work without stalling the movemet won't be as easy as it sounds.

RC
 

Aloha

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If you don't already have a movement, my advice would be to search for a movement that already has the features you are looking for. What you describe sounds simple enough to say, but building the "complication" and actually have it work without stalling the movemet won't be as easy as it sounds.

RC
That would certainly be ideal. Unforuntantly there are no movements that I've been able to find that do what I want as I have several unusual complications in mind that I've figured out mechanically gear wise but still have uncertainty regarding whether stalling due to limited power in clock movements. I also want it to be done in materials that are likely heavier then what would normally be found in clocks. For example, rather than having a very thin layer of metal that is painted with information. I'd like to make the rotating dial out of thin layer of stone with raised metal lettering. It would weigh more so would need to be built differently. I'd also like the movement to fit in as small of area as possible do to design constraints of the items.
 

Willie X

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Yes, many watches have such features but it's NOT something that could be easily made and it can't be heavy.

If you can switch your project to an electric powered clock, that might be doable with heavier parts??

Guarantee? Many? I don't think so.

Willie X
 
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bruce linde

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thin layer of stone? seriously? why would you try to work with something heavier and more prone to breakage?


materials that are likely heavier then what would normally be found in clocks.
because... that seems like a good idea to a self-described novice who apparently has not done much horological studying? the basis of good clock design is reducing the power needed as much as possible... but, i'll bite:

-day of the week is not an unheard of complication... what 'unusual' complications are you picturing?

- not sure why you think you can come up w something no one else has over the last few hundred years?

-'other people have done it'... like who? examples?
 
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zedric

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If you are looking for a way to incorporate a full calendar with a balance wheel clock, this style is one of my favorites


Here I believe the calendar is manually operated, so while it looks like it is integrated, all you need do is advance the date once a day.
 
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shutterbug

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Keep in mind that clocks were designed to operate "as is". Any added gadget will put a lot of stress on the time train that it was not designed to handle. You'll have to analyze how much power it takes to run the gadget, and whether you'll have to compensate the power source to handle it.
 
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Aloha

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Keep in mind that clocks were designed to operate "as is". Any added gadget will put a lot of stress on the time train that it was not designed to handle. You'll have to analyze how much power it takes to run the gadget, and whether you'll have to compensate the power source to handle it.
Thank you for your response, is there a proper method to analyze how much power it takes to run the complication? For example is there a tool that can measure the increased friction? Additionally, how would you compensate the power source? Change the gearing to reduce the duration the clock runs for to increase the torque? (for example make an 8 day clock only run for 4 days?). Or would you increase the mainspring strength or add a second barrel in parrallel?
 

Aloha

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If you are looking for a way to incorporate a full calendar with a balance wheel clock, this style is one of my favorites


Here I believe the calendar is manually operated, so while it looks like it is integrated, all you need do is advance the date once a day.
Is it the case that these sorts of complications are usually/only found in pendulum clocks rather than balance wheel clocks? If so why is that the case?
 

Aloha

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If you don't already have a movement, my advice would be to search for a movement that already has the features you are looking for. What you describe sounds simple enough to say, but building the "complication" and actually have it work without stalling the movemet won't be as easy as it sounds.

RC
Why couldn't you just increase the power of the mainspring to prevent stalling of the movement?
 

zedric

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Is it the case that these sorts of complications are usually/only found in pendulum clocks rather than balance wheel clocks? If so why is that the case?
The clock I linked to above is a balance wheel clock, so no, they are definitely not only found on pendulum clocks
 
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R. Croswell

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Why couldn't you just increase the power of the mainspring to prevent stalling of the movement?
You could, depending on how much additional power you need. But if you are talking about turning heavy stone "complications" I assume you are talking about a significant power increase. That will require a thicker spring of the same length (for the same run time) which will take up more space which you may or may or may not have, and definitely won't have if the spring is in a barrel. Another important consideration is the main wheel was only designed to handle the power of the original spring, if you use a significantly more powerful spring you may experience bent of failed teeth on the main wheel. Movements like in post #11 have two main wheels to divide the load. This arrangement is often used in gallery clocks which have large dials and heavy hands. If you start with a movement that's already designed for higher loading your task may be simpler. Another thing to consider is that if you use a single spring wider than 3/4" and thicker than 0.018", it will be very difficult to turn the winding key unless you add a gear reduction winding system, which would be "another complication". Tandem springs also serve to maintain power to the balance as only one spring is wound at a time. Of course, this is your contraption so you can do it anyway you like. I hope we can see the end result.

RC
 
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Aloha

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The clock I linked to above is a balance wheel clock, so no, they are definitely not only found on pendulum clocks
Thanks Zedric, I meant are complications such as dates more common on pendulum clocks then balance wheel clocks because of some limitation of balance wheel clocks? Its my understanding the clock you posted has to the calendar manually advanced each day by the owner rather than being driven by clock mainspring or did I misinterpret what you meant?
 

Aloha

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You could, depending on how much additional power you need. But if you are talking about turning heavy stone "complications" I assume you are talking about a significant power increase. That will require a thicker spring of the same length (for the same run time) which will take up more space which you may or may or may not have, and definitely won't have if the spring is in a barrel. Another important consideration is the main wheel was only designed to handle the power of the original spring, if you use a significantly more powerful spring you may experience bent of failed teeth on the main wheel. Movements like in post #11 have two main wheels to divide the load. This arrangement is often used in gallery clocks which have large dials and heavy hands. If you start with a movement that's already designed for higher loading your task may be simpler. Another thing to consider is that if you use a single spring wider than 3/4" and thicker than 0.018", it will be very difficult to turn the winding key unless you add a gear reduction winding system, which would be "another complication". Tandem springs also serve to maintain power to the balance as only one spring is wound at a time. Of course, this is your contraption so you can do it anyway you like. I hope we can see the end result.

RC
Thank you for the additional information. Is it only the main wheel that risks being damaged from the increased torque if one were to increase the strength of the mainspring. I realize this is a generalization to answer this question but I gather the reasoning is because as the power goes down each wheel away from the main wheel you are increasing speed and reducing torque so the main wheel would be the highest torque. I don't know how much extra torque I would need quantitatively but if I wanted to increase the torque by 5 fold do you think that would be too much for most mechanism to handle. The stone dials I want to add would be like powering a clock hand that weighs at most around 1 pound and probably in reasility about half that as the stones will be cut thinly.(300-500g). The weight would be spread out/balanced evenly rather than being isolated the way a clock hand is though the weight would be consentrated at the periphery rather than center. I'll send you a message with a photo of a clock similar to what I plan to do though I don't want to post the photo here because the photo is from an auction house so I'm not sure if they care about me reposting it online.
 

zedric

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Thanks Zedric, I meant are complications such as dates more common on pendulum clocks then balance wheel clocks because of some limitation of balance wheel clocks? Its my understanding the clock you posted has to the calendar manually advanced each day by the owner rather than being driven by clock mainspring or did I misinterpret what you meant?
Hi Alpha

The clock I showed does have manual adjustment, and I used that as an example because that might be the simplest design to try first.

I think it is more true that complications are more common in certain styles of clock, rather than they are less common with certain styles of escapement. For example, the more expensive carriage clocks sometimes had automatic calendars for day of the week and date, and more rarely for month and moon phase. But the market for people willing to pay for this must have been small. You even get perpetual calendars that adjust for a leap year, but these are exceptionally rare.

if you really want to build a clock with automatic complications, as has been said above, it is probably best to go for one that has an overpowered movement to start with. That way you have power to drive what you need.
 
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R. Croswell

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Thank you for the additional information. Is it only the main wheel that risks being damaged from the increased torque if one were to increase the strength of the mainspring. I realize this is a generalization to answer this question but I gather the reasoning is because as the power goes down each wheel away from the main wheel you are increasing speed and reducing torque so the main wheel would be the highest torque. I don't know how much extra torque I would need quantitatively but if I wanted to increase the torque by 5 fold do you think that would be too much for most mechanism to handle. The stone dials I want to add would be like powering a clock hand that weighs at most around 1 pound and probably in reasility about half that as the stones will be cut thinly.(300-500g). The weight would be spread out/balanced evenly rather than being isolated the way a clock hand is though the weight would be consentrated at the periphery rather than center. I'll send you a message with a photo of a clock similar to what I plan to do though I don't want to post the photo here because the photo is from an auction house so I'm not sure if they care about me reposting it online.
A lot will depend on the initial quality of the movement you begin with. Yes the main wheel, and perhaps the 2nd wheel will take most of the punishment. After that the wheels are probably durable enough. The ratchet wheel and click will probably need to be beefed up if l you use a single stronger spring. And as already mentioned, it will be a bear to wind. Tandem springs and main wheels should make it a lot easier, but if you try to add a second main wheel and spring where there was only one, you may need to beef up the 2nd arbor pinion. But until you get the rest of this contraption built and take some torque readings to determine how much power you need we are just guessing.

Don’t forget that if you over power this thing you will beat the heck out of the escapement.

RC
 

Aloha

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A lot will depend on the initial quality of the movement you begin with. Yes the main wheel, and perhaps the 2nd wheel will take most of the punishment. After that the wheels are probably durable enough. The ratchet wheel and click will probably need to be beefed up if l you use a single stronger spring. And as already mentioned, it will be a bear to wind. Tandem springs and main wheels should make it a lot easier, but if you try to add a second main wheel and spring where there was only one, you may need to beef up the 2nd arbor pinion. But until you get the rest of this contraption built and take some torque readings to determine how much power you need we are just guessing.

Don’t forget that if you over power this thing you will beat the heck out of the escapement.

RC
Is overpowering the escapement only an issue if you don't have complications to apply torque? Or does overpowering the escapement happen irregardless of the torque of the downstream movement. I would think the escapement would be independent of the torque for the most part so overpowering would happen no matter what torque is further down stream in the movement in terms of added complications. Is there a method to determine if the escapement is taking a beating from being over powered (for example the angle that the balance wheel oscillates?)
 

Aloha

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Can you guys tell me anything about this movement? Is that second key slot to make winding of the mainspring easier? If so why is there a key slot in the center of the mainspring as well? Additionally, why is the mainspring inside of a square box, isn't it usually in a round barrel? Is this a different kind of mainspring? Anything else look unusual about this movement? The movement powers two rotating stone chapter rings for the hour and minutes with one being powered from each side with only the right side visible. You can see the gear sticking out on the right side which drives the minute or hour chapter ring. Does the balance wheel looked beefed up to be more powerful? This is a pretty small desktop clock but has to be powerful enough to power 2 stone dials.

Screen Shot 2019-08-21 at 3.04.10 PM.png
 

zedric

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Sorry, more questions than answers..

What is this movement designed for? How big is it? Are you saying that this movement drives two stone rings, or that you want a movement to be able to drive two stone rings?
 

Aloha

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Sorry, more questions than answers..

What is this movement designed for? How big is it? Are you saying that this movement drives two stone rings, or that you want a movement to be able to drive two stone rings?
This is a small movement for a desk clock. Its about 3-4 inches across for the entire visible portion. Its designed to move 2 thin rock crystal dials that are about 5 inches across for the minute and hour hands. It has two shafts not shown that transmit the power up to each crystal dial above which are powered by a single gear on each side sticking off to the side, you can only see the right side next to the hole for the shaft. Do you understand why there is 2 winding arbors? I assume that square post in the center is a winding arbor for the the mainspring as well. I'm guessing that it makes winding the mainspring easier using gears which is why its not in the center of the mainspring? The question is why is there also a winding arbor in the center of the "mainspring box" assuming that square box is truly the mainspring barrel. Does this suggest that the mainspring's strength was increased to give it more power and thats why the second square post is there in the center and they just left the original there because its likely a standard part? This is a very expensive clock this came from so you would think the parts would have been custom made. Is a square mainspring box found in any other mainsprings you are aware of or am I completely misinterpreting what that box is. I always through mainsprings were in round barrels?
 
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R. Croswell

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Is overpowering the escapement only an issue if you don't have complications to apply torque? Or does overpowering the escapement happen irregardless of the torque of the downstream movement. I would think the escapement would be independent of the torque for the most part so overpowering would happen no matter what torque is further down stream in the movement in terms of added complications. Is there a method to determine if the escapement is taking a beating from being over powered (for example the angle that the balance wheel oscillates?)
The escapement needs a constant amount of power to be a reliable time keeper. Generally 360 degrees balance rotation would be OK. Too much power and it will slam back and forth and possibly damage itself or shorten its life. Being at the top of the train, the balance gets what's left after power of the spring is reduced by friction and whatever complications the movement is driving. You should try to balance everything so the power use before the balance remains constant.

RC
 

Aloha

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The escapement needs a constant amount of power to be a reliable time keeper. Generally 360 degrees balance rotation would be OK. Too much power and it will slam back and forth and possibly damage itself or shorten its life. Being at the top of the train, the balance gets what's left after power of the spring is reduced by friction and whatever complications the movement is driving. You should try to balance everything so the power use before the balance remains constant.

RC
By balance everything so the power use before the balance remains constant you mean that if I add a complication that adds 10 units of torque I should make sure the increased mainspring adds only 10 units of torque and not more because if I add more that will then cause the balance wheel to slam back and forth more then before.
 

R. Croswell

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By balance everything so the power use before the balance remains constant you mean that if I add a complication that adds 10 units of torque I should make sure the increased mainspring adds only 10 units of torque and not more because if I add more that will then cause the balance wheel to slam back and forth more then before.
Yes and no. That's the general idea as far as how much power to provide, but by "balance" I was referring to physically balancing the moving parts. For example, if a clock has a very long and heavy minute hand that reaches from the center arbor to the chapter ring, the movement will need to provide more power to raise the hand against gravity moving from 6:00 to 12:00 but from 12:00 to 6:00 gravity will pull the hand down requiring zero power from the movement. Now if you add a counterweight of the correct size to the tail end of the hand, the counterweight will offset the effect of gravity on the minute hand. I'm having trouble visualizing your stone "complications", but I'm suggesting that they be balanced well such that gravity will have neutral affect on them. The stone parts could be quite heavy but if well balanced and supported by low friction bearings would require very little power to keep moving at a constant speed.

RC
 
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novicetimekeeper

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complications, like date, day, month, lunar date, phase of moon, tidal state, relative position of planets to the sun, and more, have existed on spring and gravity driven clocks since before the pendulum was invented.
 
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gmorse

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complications, like date, day, month, lunar date, phase of moon, tidal state, relative position of planets to the sun, and more, have existed on spring and gravity driven clocks since before the pendulum was invented.
And in watches with significantly less power.

As I understand Aloha's requirements, these include a horizontal chapter ring, which would not be subject to uneven gravitational effects in the same way as the hands on a vertical dial, but would of course possess inertia. Since the whole wheel train doesn't run continuously but stops and starts with every swing of the balance, inertia can become a significant factor.

On the example movement, the right-hand square is clearly the mainspring arbor, it has a ratchet and click in the usual way. The left-hand square looks as though it's on the centre arbor, so could be for hand setting. I agree that the square box is odd; does it perhaps contain a second mainspring barrel superimposed on one below the back plate, winding and running in tandem?

Regards,

Graham
 
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Aloha

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Yes and no. That's the general idea as far as how much power to provide, but by "balance" I was referring to physically balancing the moving parts. For example, if a clock has a very long and heavy minute hand that reaches from the center arbor to the chapter ring, the movement will need to provide more power to raise the hand against gravity moving from 6:00 to 12:00 but from 12:00 to 6:00 gravity will pull the hand down requiring zero power from the movement. Now if you add a counterweight of the correct size to the tail end of the hand, the counterweight will offset the effect of gravity on the minute hand. I'm having trouble visualizing your stone "complications", but I'm suggesting that they be balanced well such that gravity will have neutral affect on them. The stone parts could be quite heavy but if well balanced and supported by low friction bearings would require very little power to keep moving at a constant speed.

RC
Ok thanks, I understand what you mean by balanced, thank you fo. In regards to using low friction bearings. I am looking into small precision ceramic ball bearings. I understand clocks use jewels and also metals holes with pivots inside. Is there a benefit other then cost to using metal on metal as opposed to using jewels (or ball bearings) in certain applications? For example if the gear is turning slower than once per 24 hours there is no benefit to using jewels/ball bearings?
 

Aloha

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And in watches with significantly less power.

As I understand Aloha's requirements, these include a horizontal chapter ring, which would not be subject to uneven gravitational effects in the same way as the hands on a vertical dial, but would of course possess inertia. Since the whole wheel train doesn't run continuously but stops and starts with every swing of the balance, inertia can become a significant factor.

On the example movement, the right-hand square is clearly the mainspring arbor, it has a ratchet and click in the usual way. The left-hand square looks as though it's on the centre arbor, so could be for hand setting. I agree that the square box is odd; does it perhaps contain a second mainspring barrel superimposed on one below the back plate, winding and running in tandem?

Regards,

Graham
Thats an interesting idea regarding the mainspring box... I want to make sure I understand what you mean by a second mainspring superimposed on the other. If they are superimposed they would be centered on the same axis so would be in parrallel which would allow them to supply double the torque and would last the same 8 days? You might be on to the second post having to do with time setting as that post sticks out the bottom of the clock case so is accessible when you pick up the clock and flip it over to wind the clock. This clocks design would not allow one to simply move the clock hands so I think you almost certainly must be correct. The question would be how it could operate on this type of clock. When your setting a regular clock and moving the minute hand to set it I understand there is a slip clutch on the arbor shaft. For this design you somehow need to activate the gear on the side without it also activating back up the gears in the clock movement. I'm guessing a slip clutch is also needed in this case but the question of where it would go is something I can't think of off the top of my head at this moment. Lastly, do you have any guess what those 2 silver half circles are at the bottom?
 
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R. Croswell

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Ok thanks, I understand what you mean by balanced, thank you fo. In regards to using low friction bearings. I am looking into small precision ceramic ball bearings. I understand clocks use jewels and also metals holes with pivots inside. Is there a benefit other then cost to using metal on metal as opposed to using jewels (or ball bearings) in certain applications? For example if the gear is turning slower than once per 24 hours there is no benefit to using jewels/ball bearings?
I would think that ball bearings would have an advantage when heavy parts need to be supported.

RC
 
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gmorse

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Hi Aloha,
want to make sure I understand what you mean by a second mainspring superimposed on the other. If they are superimposed they would be centered on the same axis so would be in parrallel which would allow them to supply double the torque and would last the same 8 days?
Yes, the duration would not be altered if both springs were on the same arbor, but there would be more torque available.

I'm guessing a slip clutch is also needed in this case but the question of where it would go is something I can't think of off the top of my head at this moment. Lastly, do you have any guess what those 2 silver half circles are at the bottom?
There would have to be a clutch of some sort between the centre arbor and the cannon pinion (or its equivalent) which drives the minute hand or indicator, and which in turn drives the hour hand through a 12:1 reduction gearing, usually achieved in two steps with the minute wheel as the intermediary.

If you mean the two steel screws at the bottom with partial heads, they appear to be dog screws and are holding the movement on the mounting plate. They allow its removal without having to unscrew them completely.

Regards,

Graham
 
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RJSoftware

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A jump spring/lever takes advantage of snail. Riding on snail edge, at 12 the lever snaps down from 1:00 edge to the 12:00. (notice backwards). Depending on size of the snail, the lever moves a significant amount. Like 1/2 inch+. Multiply by 2 (2x12=24 hours).

That mechanical action is transformed into calendar day/date movement.

The backwards snail gradually lifts the spring loaded lever back up during next 12 hours. The gradual lift prevents strain on time side keeping.

This part of design is good for day of the week.
So you could portion out a disk/drum as follows:

Mon am
Mon pm
Tue am
Tue pm
Wed am etc.

Each lever push increments 1/14th a turn.
Typically a disk has notches like circular saw blade for lever to push.
A separate spring provides tension so lever push is only one direction.
It just fits in saw blade notch assuring increment is correct.

You can manually turn disc by hand to initially set.
 
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Aloha

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A jump spring/lever takes advantage of snail. Riding on snail edge, at 12 the lever snaps down from 1:00 edge to the 12:00. (notice backwards). Depending on size of the snail, the lever moves a significant amount. Like 1/2 inch+. Multiply by 2 (2x12=24 hours).

That mechanical action is transformed into calendar day/date movement.

The backwards snail gradually lifts the spring loaded lever back up during next 12 hours. The gradual lift prevents strain on time side keeping.

This part of design is good for day of the week.
So you could portion out a disk/drum as follows:

Mon am
Mon pm
Tue am
Tue pm
Wed am etc.

Each lever push increments 1/14th a turn.
Typically a disk has notches like circular saw blade for lever to push.
A separate spring provides tension so lever push is only one direction.
It just fits in saw blade notch assuring increment is correct.

You can manually turn disc by hand to initially set.
I understand most of this but what is the purpose of Mon AM Mon PM? I understand there are 2 twelve hour increments in a day. You'd some how need to make the snail turn every 24 hours rather then every 12 pollisbly though having it on a separate arbor geared down 1:2. Otherwise you'd get halfway between Monday and Tuesday (DAY TUE) rather then (TUESDAY) in the window would you not? I understand most of what you wrote but also don't understand the "backwards" snail. What is the purpose of it being backwards. How is that different than a traditional snail cam? Its my understanding the snail raises the lever which snaps back when the snail drops off and during that snap back it has something to catch and flick the date wheel 1 increment so it advances from Monday to Tuesday for example or in the case of a Jump Hour 1 o'clock to 2 o'clock. Is that correct or am I missing something. I gather this was describing an instantaneous advance as apposed to a gradual sweeping advance (for example at 12:00 midnight the day changes immediately rather then sweeping over 24 hours to the next day)
"A separate spring provides tension so lever push is only one direction." I'm guessing this is so when the snail cam gradually raises over the 12 hours it doesn't change the date backwards? For example going Tuesday to Monday? For example you could have a ratchet type where the catch for the lever only catches on the downward snail cam drop but pushes the catch out of the way as it advances on the hour? If I'm not understanding you correctly please correct me. Thanks again as this is something I am specifically intersted in doing in doing for various complications. Regards

Thank you for sharing this.
 

RJSoftware

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Ok, my example is based on actual clock. Don't let the convoluted world of clock/watch terminology mess up the comprehension. The terminology is messed up because things evolve but often terms stick even nonsensical ones. So a jump day would be more accurate.

The splitting of a full 24 hour day into 2 12 hour units (am & pm) simplify the jump day cam ( backwards snail). A simple friction fit to the hour cannon tube. It is fitted on before the hour hand, behind dial.

So no need for any extra gearing. Just as the time hits 12:00 am or pm the lever drops off edge and spring slams lever down. That force is used to increment day dial.

I was trying to explain the incremental assurance spring (forgot actual name).

Picture a circular saw blade. But this is your day of the week dial. Instead of 7 teeth, 14 teeth (each day having am & pm). So 14 teeth/increments.

Picture that dial on it's own arbor, by itself. You could spin it, but where would it land? So, You could bend a small spring. Just like the letter C. You could mount that C so that the C's curve could push into and between any 2 of the saw blade tips. Forcing the dial to advance to exact correct spot. Otherwise when the lever increments, the dial might land crooked etc..

You see this kind of spring I think in moon dials etc.. A dial position assurance spring.
 
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RJSoftware

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On my clock, which I intend to do same as you, it came from factory with backwards snail/cam. But previous owner stripped out all the day of week hardware. I did scads of research and found someone who gave me pics that I one day plan to duplicate. It's a National Recorder Time clock.

The incrementing lever is guided to the saw teeth by slot. The slot has no top, so the lever lift upwards enough when withdrawing to rise over previous saw tip to drop back down into next. Shaped like a field goal post, except the 2 uprights snug against lever to guide it.

All the lever has to do is push against dial increment tooth (saw tooth) far enough that assurance C spring takes over and sets it in place. But it has to also continually position itself for alignment of next jump increment. So it has to rise up/down slightly by the field post guide. An additional smaller spring can assure good seating by pulling lever downward to rest in dip before dial increment tooth.
 
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Aloha

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On my clock, which I intend to do same as you, it came from factory with backwards snail/cam. But previous owner stripped out all the day of week hardware. I did scads of research and found someone who gave me pics that I one day plan to duplicate. It's a National Recorder Time clock.

The incrementing lever is guided to the saw teeth by slot. The slot has no top, so the lever lift upwards enough when withdrawing to rise over previous saw tip to drop back down into next. Shaped like a field goal post, except the 2 uprights snug against lever to guide it.

All the lever has to do is push against dial increment tooth (saw tooth) far enough that assurance C spring takes over and sets it in place. But it has to also continually position itself for alignment of next jump increment. So it has to rise up/down slightly by the field post guide. An additional smaller spring can assure good seating by pulling lever downward to rest in dip before dial increment tooth.
Ok I think I understand this now at least mostly. I still don't fully grasp how at noon it doesn't advance 1/2 way but I think its because the saw teeth have enough space that only every other pulse is enough to advance the saw tooth forward one click (some howbecause of the spring holding it in place stops the advance? or is the spring just supposed to make it only advance 1 click and its that there's play so only every other pulse strikes the saw tooth?.
I find myself fascinated with jump hours and retrogrades and one of the designs I want to make is a combination with a jump hour retrograde. I understand how to do a traditional retrograde and a traditional jump hour mostly but the combination has me confused. I understand you'd need a modification of a snail cam which instead of having smooth step ups would have incremental step ups with 12 steps in the 360 degrees followed by a drop off. However, I think you would almost have to go in the reverse direction and only step down though and "climb down the stairs" of the cam because you obviously can't step up. This becomes an issue though after 12 hours is done. Somehow you'd have to find a way to step it back up at the end of the 12 hour period though I haven't figured it out yet but will continue thinking about it. I'm sure a retrograde jump hour is possible the question is how.
 

RJSoftware

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The jump happens only at the 12 o'clock hour.
One jump at 12 am and one at 12 pm.

The jump pushes the lever one click. The day of week dial is divided in 14 sections with an AM an PM for each day.

MON AM
MON PM
TUE AM
TUE PM
WED AM
WED PM
THU AM
THU PM
FRI AM
FRI PM
SAT AM
SAT PM
SUN AM
SUN PM

On mine the day of week dial is hidden behind panel. A rectangular hole shows the current day on day of week dial. The C spring centers dial text in the rectangular hole.
 
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RJSoftware

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The reverse snail description was just to give you a visual. The snail is smooth no bump/stairs.

The hand only goes forward. If you pushed hand backwards the tall edge f backwards snail might bend the lever.

So the lever slides up smooth edge and falls at the 12:00
 
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Aloha

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The jump happens only at the 12 o'clock hour.
One jump at 12 am and one at 12 pm.

The jump pushes the lever one click. The day of week dial is divided in 14 sections with an AM an PM for each day.

MON AM
MON PM
TUE AM
TUE PM
WED AM
WED PM
THU AM
THU PM
FRI AM
FRI PM
SAT AM
SAT PM
SUN AM
SUN PM

On mine the day of week dial is hidden behind panel. A rectangular hole shows the current day on day of week dial. The C spring centers dial text in the rectangular hole.
Ok, I get it now. Didn't realize day of the week clocks advance it at noon as well but have it written twice. I guess thats one solution.
 

gmorse

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Hi Aloha,
The reverse snail description was just to give you a visual. The snail is smooth no bump/stairs.

The hand only goes forward. If you pushed hand backwards the tall edge f backwards snail might bend the lever.

So the lever slides up smooth edge and falls at the 12:00
This is how instantaneous minute registers work on some chronographs. When the lever tail drops off the largest diameter of the snail on the centre seconds arbor, the pin on the other side of it pulls the minute register wheel round by one tooth. It's prevented from doing this by the reset hammer when the chronograph is stopped.

DSCF5113.JPG

Regards,

Graham
 

RJSoftware

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Yes, a simple clean solution. I suppose instead of the reverse snail fitted to the hour cannon, you could fit a gear, then drive another gear with double the teeth (so it's one revolution takes 24 hours). Then fit reverse snail to that. Then you get 1 jump per a full day. But I like the am pm distinction. Also, it's primitive cool.

I don't know if you have gear cutting equipment but it is also true you can cut everything with hand saws and fine files. The tooling is extremely expensive, difficult to obtain. The manual cutting and filing is do-able but takes high skill, practice. Making your own tool jigs to do controlled filing and precise increments, I think the way to go.

But the 14 teeth day-of-week dial and the reverse snail could easily done by hand tools, no jigs either. Once again, primitive cool.

I think making the dial first would establish the increment push length required. So whatever measure that turns out to be, would be the amount of drop the jump should provide.

If the d-o-w dial is somehow still accessible behind panel the it's adjustment (setting to correct day, am/pm) can simply be adjusted by hand.

Else, like mine, a separate lever with spring pushes the increment lever. But I like the simplicity of adjustment by hand.A small portion of the dial exposed at bottom good enough.

The C spring was just a simplified description to explain the simple way the dial position is maintained. The C spring would actually be more profiled to the shape of dip between teeth, perpendicular to teeth, the wide side providing tension enough to roll dial into precise location by the profile mating. Simple
 
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Aloha

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Last question. Is there a specific clock movement type that has less wasted open space. I realize the smaller the components the weaker they are. For example a smaller mainspring is likely weaker. However clock movements seem to have a lot of wasted space. I want to fit the movement in as small of an area as possible. Does anyone have suggestions for more compact clock movements that also happen to be just as strong?
 

RJSoftware

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You could build your own. Use gears, levers and pillars from an existing movement and make new plates. You could then construct a tighter configuration, not by mesh depth, because mesh must always be 90% engagement with 10% airspace, but by rolling contact along perimeter.
You could use a simple 2 needle compass to scratch out arcs in existing pivot holes to triangulate bushing hole position. If you don't mind extra holes you simply modify existing plates. Good for trial run.

You could purchase or make a clock sized depthing tool. A good tool to have anyway. Then you could go to town on building your own..!

Consider the small size of average size clock tooth. Now divide that small measure by 10. Yes, we is in estimation land. I think as long as you see a wee bit of light between gear teeth and when gears feel rolling good, you got the measure. That's what the tool is for.
 

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